Cold start knock
05-30-20, 09:40 AM
#1
Driver School Candidate
Thread Starter
Cold start knock
My 2000 ls400 sometimes make knocking sound like rod knock when cold start. Doesn’t happen all the time but if I let it sit for few days and temperatures little bit cold it might make the noise. Will go away in 30 40 seconds. If i crank and drive everyday, it doesn’t happen at all. Not sure what I need to do to correct this problem
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tuanhuy030 (05-30-20)
05-30-20, 04:36 PM
#4
Rockers as in rocker arms? There are none.
Two questions - what grade (viscosity) oil and what brand of oil filter are you using?
Too heavy of an oil will be slow to circulate when cold.
Regarding the oil filter, sometimes it's the anti-drainback valve (or lack of one) in the filter that's either failing or is simply of poor design. Think of it as a drinking straw. Put your thumb over the end of the straw and pull it out of your drink. Notice how the liquid remains in the straw? Remove your thumb and the liquid pours out. Your thumb is analogous to the filters anti-drainback valve.
Start up knock should go away in a few seconds. Thirty to forty seconds in a long time.
Two questions - what grade (viscosity) oil and what brand of oil filter are you using?
Too heavy of an oil will be slow to circulate when cold.
Regarding the oil filter, sometimes it's the anti-drainback valve (or lack of one) in the filter that's either failing or is simply of poor design. Think of it as a drinking straw. Put your thumb over the end of the straw and pull it out of your drink. Notice how the liquid remains in the straw? Remove your thumb and the liquid pours out. Your thumb is analogous to the filters anti-drainback valve.
Start up knock should go away in a few seconds. Thirty to forty seconds in a long time.
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tuanhuy030 (05-30-20)
05-30-20, 04:53 PM
#5
Moderator
My 2000 ls400 sometimes make knocking sound like rod knock when cold start. Doesn’t happen all the time but if I let it sit for few days and temperatures little bit cold it might make the noise. Will go away in 30 40 seconds. If i crank and drive everyday, it doesn’t happen at all. Not sure what I need to do to correct this problem
Last edited by Yamae; 05-30-20 at 04:56 PM.
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tuanhuy030 (05-30-20)
05-30-20, 06:10 PM
#6
Lexus Champion
Are you using a cheap XX-30 type oil and filter? How cold it is where you live?
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tuanhuy030 (05-30-20)
05-30-20, 08:30 PM
#7
Driver School Candidate
Thread Starter
Rockers as in rocker arms? There are none.
Two questions - what grade (viscosity) oil and what brand of oil filter are you using?
Too heavy of an oil will be slow to circulate when cold.
Regarding the oil filter, sometimes it's the anti-drainback valve (or lack of one) in the filter that's either failing or is simply of poor design. Think of it as a drinking straw. Put your thumb over the end of the straw and pull it out of your drink. Notice how the liquid remains in the straw? Remove your thumb and the liquid pours out. Your thumb is analogous to the filters anti-drainback valve.
Start up knock should go away in a few seconds. Thirty to forty seconds in a long time.
Two questions - what grade (viscosity) oil and what brand of oil filter are you using?
Too heavy of an oil will be slow to circulate when cold.
Regarding the oil filter, sometimes it's the anti-drainback valve (or lack of one) in the filter that's either failing or is simply of poor design. Think of it as a drinking straw. Put your thumb over the end of the straw and pull it out of your drink. Notice how the liquid remains in the straw? Remove your thumb and the liquid pours out. Your thumb is analogous to the filters anti-drainback valve.
Start up knock should go away in a few seconds. Thirty to forty seconds in a long time.
Your words "If i crank and drive everyday, it doesn’t happen at all." reminds me of a poorly made oil filter especially the anti drain-back valve is not working right. This often happens among poorly made oil filters that do not use a good material for the valve. Do you use a Toyota oil filter?
I always use 5w30 mobil 1 with oem filter 90915-yzzd1. Oil always change under 5k miles. It is not really cold down here in GA, just a cool day around 60 65 could give it problem
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05-30-20, 10:07 PM
#8
Lexus Champion
Switch to the mobile 1/pureolator boss/amsoil/farm ultra synthetic and make sure you are using the extended performance blend not the regular stuff that is questionable. Use something like that or pensoil ultra platinum/amsoil/royal purple to rule out an oil or filter issue.
If it persists it's probably an issue with valve adjustment since the 1UZ doesn't have self adjusting valves but that would be extremely strange since they almost never need to be adjusted even after 200k miles they are 99% of the time in spec
Anything past those and you have a oiling system problem or parts that were at the edge of tolerance stacking or very worn for whatever reason, again all very unlikely with a 1UZ
If it persists it's probably an issue with valve adjustment since the 1UZ doesn't have self adjusting valves but that would be extremely strange since they almost never need to be adjusted even after 200k miles they are 99% of the time in spec
Anything past those and you have a oiling system problem or parts that were at the edge of tolerance stacking or very worn for whatever reason, again all very unlikely with a 1UZ
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tuanhuy030 (05-30-20)
05-30-20, 10:26 PM
#9
Driver School Candidate
Thread Starter
Switch to the mobile 1/pureolator boss/amsoil/farm ultra synthetic and make sure you are using the extended performance blend not the regular stuff that is questionable. Use something like that or pensoil ultra platinum/amsoil/royal purple to rule out an oil or filter issue.
If it persists it's probably an issue with valve adjustment since the 1UZ doesn't have self adjusting valves but that would be extremely strange since they almost never need to be adjusted even after 200k miles they are 99% of the time in spec
Anything past those and you have a oiling system problem or parts that were at the edge of tolerance stacking or very worn for whatever reason, again all very unlikely with a 1UZ
If it persists it's probably an issue with valve adjustment since the 1UZ doesn't have self adjusting valves but that would be extremely strange since they almost never need to be adjusted even after 200k miles they are 99% of the time in spec
Anything past those and you have a oiling system problem or parts that were at the edge of tolerance stacking or very worn for whatever reason, again all very unlikely with a 1UZ
05-30-20, 11:14 PM
#10
Lexus Champion
It might let air enter the oil galley and have the same effect as a substandard anti drain-back valve, I would correct that if the problem persists through a the better filter
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Yamae (05-31-20)
06-01-20, 08:41 PM
#11
Pole Position
My 2000 ls400 sometimes make knocking sound like rod knock when cold start. Doesn’t happen all the time but if I let it sit for few days and temperatures little bit cold it might make the noise. Will go away in 30 40 seconds. If i crank and drive everyday, it doesn’t happen at all. Not sure what I need to do to correct this problem
Try removing the serpentine belt before starting and listen for any difference...
In the process of elimination, perform an oil pressure test.
Try also using 0W-30 synthetic instead of 5W-30...better cold-start viscosity. (Google it)
Use Toyota brand filter.
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